Measuring and testing – Vehicle chassis – Steering
Patent
1999-02-08
2000-12-12
McCall, Eric S.
Measuring and testing
Vehicle chassis
Steering
G01M 1500
Patent
active
061582735
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method and to a device for detection of misfiring of an internal combustion engine, in which the torque of the internal combustion engine is measured by means of a torque sensor arranged on the crankshaft of the internal combustion engine and where a torque signal is sampled speed-synchronously.
BACKGROUND OF THE INVENTION
Misfiring of internal combustion engines is an operational disturbance which implies that the fuel/air mixture compressed in the cylinder is not completely burnt, or not burnt at all, for example because of a failing ignition spark (Otto engine) or disturbances during injection (Diesel engine). It therefore results in reduced power of the internal combustion engine, increased wear on components included and, in addition, entails increased emission of environmentally harmful substances as, for example, unburnt hydrocarbon compounds. Misfiring also contributes to reduction of the service life of the exhaust gas catalytic converter of the internal combustion engine. Detecting and indicating misfiring is, therefore, of great importance for an increased service life of internal combustion engines. Detection also permits a possibility of reducing the environmental influence and of complying in a better way with the increasingly stricter demands made by the legislation on emission of various pollutants from internal combustion engines.
One way of defining misfiring is based on the work which is carried out in each cylinder during a work cycle, which, in the case of a conventional four-stroke Otto engine or diesel engine, consists of two crankshaft turns (720.degree.). If the work for a cylinder is insignificant in relation to the amount of fuel present in the cylinder, it can be said that, by definition, misfiring has taken place. As a measure of this work, a so-called indicated mean effective pressure (IMEP) is often used, which is obtained by dividing the measured work by the piston displacement of the cylinder.
Misfiring can be detected in a plurality of different ways.
A direct measurement of the cylinder pressure in each individual cylinder may, of course, be used for detecting misfiring. Because of the severe environment in which the necessary pressure sensors are to operate, the method is costly and has substantially been used only in very large internal combustion engines. Since the method is based on a comparison of the output signals from several different sensors, varying aging between the sensors may lead to problems with the reliability of the method after a long time. In addition, it is necessary to have access to the crank angle for each cylinder with great accuracy in order for the calculation of the work carried out to become reliable.
Another method for detecting misfiring comprises measuring the electrical conductivity of the gas present in the cylinders of the internal combustion engine. This measurement may be performed by using the spark plug of the respective cylinder as measuring electrode. Such a method is described, for example, in U.S. Pat. No. 5,207,200. During a misfire, the gas in the cylinder becomes colder than after a successful ignition, and the gas therefore has a lower conductivity during a misfire. An advantage of this method is that an electrical quantity may be measured directly without needing access to a separate sensor. However, the method places special demands on the design of the ignition system of the internal combustion engine. As an example, it may be mentioned that special spark plugs are required as well as a separate ignition coil for each cylinder. Problems may arise due to varying aging of the spark plugs and the reliability during no-load operation, acceleration and braking is not good. This, method makes demands for a very high calculation capacity. Additional methods for detecting misfiring are based on measurement of the engine speed, see, for example, U.S. Pat. No. 5,216,915 and U.S. Pat. No. 5,278,760. To equalize the power of the normal torque fluctuations of the internal combustio
REFERENCES:
patent: 5207200 (1993-05-01), Iwata
patent: 5216915 (1993-06-01), Sakamoto
patent: 5269178 (1993-12-01), Vigmostad et al.
patent: 5278760 (1994-01-01), Ribbens et al.
patent: 5313826 (1994-05-01), Klauber et al.
patent: 5353636 (1994-10-01), Sakurai et al.
patent: 5495774 (1996-03-01), Klauber et al.
patent: 5675094 (1997-10-01), Klauber et al.
patent: 5856922 (1999-01-01), Jehanno
patent: 5869752 (1999-02-01), Klauber et al.
patent: 5902934 (1999-05-01), Sprague et al.
Vaidyanathan, Design and Implementation of Digital FIR Filters, Chapter 2, 12/ Handbook of Digital Signal Processing, pp. 55-67, Academic Press, Inc. 1987.
Jeremiasson Jan
Sobel Jarl
Wallin Christer
Asea Brown Boveri AB
McCall Eric S.
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